Update shelf spacing in Chrome OS according to the MD specs

ash/common/shelf/shelf_constants.h

Index: ash/common/shelf/shelf_constants.h
diff --git a/ash/common/shelf/shelf_constants.h b/ash/common/shelf/shelf_constants.h
index aa3caab1a19080cb8116a1aa1b4ca6c62d1aa5bb..ea85e66a6111bfd81dde5a0839f453ee479b7cb9 100644
--- a/ash/common/shelf/shelf_constants.h
+++ b/ash/common/shelf/shelf_constants.h
@@ -12,22 +12,38 @@ namespace ash {
 
 enum ShelfConstant {
   // The alpha value for the shelf background when a window is overlapping.
-  SHELF_BACKGROUND_ALPHA
+  SHELF_BACKGROUND_ALPHA,
+
+  // Size of the shelf when visible (height when the shelf is horizontal and
+  // width when the shelf is vertical).
+  SHELF_SIZE,
+
+  // Size of the space between buttons on the shelf.
+  SHELF_BUTTON_SPACING,
+
+  // Size allocated for each button on the shelf.
+  SHELF_BUTTON_SIZE
 };
 
 // Invalid image resource id used for ShelfItemDetails.
 extern const int kInvalidImageResourceID;
 
-const int kInvalidShelfID = 0;
+// We reserve a small area on the edge of the workspace area to ensure that
+// the resize handle at the edge of the window can be hit.
+extern const int kWorkspaceAreaVisibleInset;
+
+// When autohidden we extend the touch hit target onto the screen so that the
+// user can drag the shelf out.
+extern const int kWorkspaceAreaAutoHideInset;
 
-// Size of the shelf when visible (height when the shelf is horizontal).
-ASH_EXPORT extern const int kShelfSize;
+// Size of the shelf when auto-hidden.
+ASH_EXPORT extern const int kShelfAutoHideSize;
 
-// Size of the space between buttons on the shelf.
-ASH_EXPORT extern const int kShelfButtonSpacing;
+// Inset between the inner edge of the shelf (towards centre of screen), and
+// the shelf items, notifications, status area etc.
+extern const int kShelfItemInset;
 
-// Size allocated for each button on the shelf.
-ASH_EXPORT extern const int kShelfButtonSize;
+const int kInvalidShelfID = 0;
 
 // Animation duration for switching black shelf and dock background on and off.
 ASH_EXPORT extern const int kTimeToSwitchBackgroundMs;